I make it twenty changes if you only save $2.50 a time. That's assuming the contraption and all its seals survive 20 wrenchings. -- Phil Payne, Isham Research 21 Bramwell Court, Sheffield S3 7PR http://www.isham-research.freeserve.co.uk Phone/SMS: +44 7785 302803 Fax: +44 7785 309674